3:45 PM Abstract No. 195 Leveraging transarterial chemoembolization–induced metabolic reprogramming and CRISPR-based genome editing to identify latent tumor viability with DNP-13C-NMRS in hepatocellular carcinoma

Abstract

Transarterial chemoembolization (TACE) is used to treat advanced hepatocellular carcinoma (HCC). By restricting a tumor’s arterial supply, TACE facilitates local reduction in oxygen and nutrients. While TACE slows disease progression, recurrence occurs in the majority of cases. Latent tumor cell viability has been shown to enable recurrence, which current diagnostic imaging fails to identify. The purpose of this study was to identify DNP-13C-NMRS probes sensitive to ischemia-induced metabolic reprogramming of HCC cells surviving TACE. To identify a probe sensitive to post-TACE viability, we utilized a technique developed by our lab to predict DNP-13C-NMRS probe efficacy with CRISPR-based screening. We investigated enzymes essential to HCC cells grown in a post-TACE microenvironment by performing screens in SNU-449 cells under conditions in which nutrients and O2 were either abundant or deplete. Targeted sequencing quantified relative enzyme essentiality between conditions, facilitating selection of DNP-13C-NMRS probes metabolized by candidate enzymes. CRISPR-based screening revealed that HCC cells grown under ischemia-mimicking conditions differentially rely on NADPH-dependent reductases for growth, including G6PD (LFC = -1.09, P = 4.98e-6, FDR = 8.87e-4) and TXN (LFC = -1.75, P = 4.98e-6, FDR = 8.87e-4). GLS, which is responsible for conversion of glutamine to glutamate, was also a differential vulnerability of ischemic HCC cells (LFC = -0.64, P = 3.34e-4, FDR = 0.03). DNP-13C-NMRS probes metabolized by these enzymes include [1-13C]-dehydroascorbate and [1-13C]-glutamine. We have successfully prepared DNP-[1-13C]-dehydroascorbate and have measured intratumoral formation of ascorbate in a DEN model of HCC in rats. Cells surviving TACE alter their metabolism in response to nutrient and oxygen deprivation. With an unbiased screening approach, we identified enzymes that are differentially essential to growth under these conditions. In vivo assessment of DNP-[1-13C]-dehydroascorbate and DNP-[1-13C]-glutamine metabolism will provide a functional readout of tumor metabolism that we hypothesize will isolate latent tumor viability that follows TACE and precedes recurrence.